{"id":"CVE-2026-55064","state":"PUBLISHED","title":"Vikunja incomplete fix for CVE-2026-35595: Write-only user can detach shared project from parent hierarchy via parent_project_id=0","description":"Vikunja is an open-source self-hosted task management platform. From 2.3.0 until 2.4.0, a user with Write but not Admin permission on a shared child project can detach it from its parent hierarchy by submitting parent_project_id equal to 0 to POST /api/v1/projects/{project}. The Project.CanUpdate authorization check in pkg/models/project_permissions.go and UpdateProject logic in pkg/models/project.go only gate nonzero parent values, while UpdateProject always persists parent_project_id, so the explicit zero value bypasses the Admin requirement introduced for CVE-2026-35595. Detachment severs the recursive permission-inheritance chain and can disrupt the owner’s hierarchy and inherited collaborator access. This issue is fixed in version 2.4.0.","publishedAt":"2026-08-28T16:38:38.293Z","updatedAt":"2026-08-28T20:29:30.143Z","severity":{"score":4.3,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["go-vikunja vikunja"],"affected":[{"vendor":"go-vikunja","product":"vikunja","versions":[{"version":">= 2.3.0, < 2.4.0","status":"affected"}]}],"references":["https://github.com/go-vikunja/vikunja/security/advisories/GHSA-44v6-7fxq-vgf4","https://github.com/go-vikunja/vikunja/pull/3239","https://github.com/go-vikunja/vikunja/commit/781ffac198548ae4f3d1febc613caed8e0e11d01","https://github.com/go-vikunja/vikunja/releases/tag/v2.4.0"],"weaknesses":["CWE-862"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/55xxx/CVE-2026-55064.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-55064","state":"PUBLISHED","datePublished":"2026-08-28T16:38:38.293Z","dateUpdated":"2026-08-28T20:29:30.143Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-16T14:33:35.710Z"},"containers":{"cna":{"title":"Vikunja incomplete fix for CVE-2026-35595: Write-only user can detach shared project from parent hierarchy via parent_project_id=0","descriptions":[{"lang":"en","value":"Vikunja is an open-source self-hosted task management platform. From 2.3.0 until 2.4.0, a user with Write but not Admin permission on a shared child project can detach it from its parent hierarchy by submitting parent_project_id equal to 0 to POST /api/v1/projects/{project}. The Project.CanUpdate authorization check in pkg/models/project_permissions.go and UpdateProject logic in pkg/models/project.go only gate nonzero parent values, while UpdateProject always persists parent_project_id, so the explicit zero value bypasses the Admin requirement introduced for CVE-2026-35595. Detachment severs the recursive permission-inheritance chain and can disrupt the owner’s hierarchy and inherited collaborator access. This issue is fixed in version 2.4.0."}],"affected":[{"vendor":"go-vikunja","product":"vikunja","versions":[{"version":">= 2.3.0, < 2.4.0","status":"affected"}]}],"references":[{"url":"https://github.com/go-vikunja/vikunja/security/advisories/GHSA-44v6-7fxq-vgf4","name":"https://github.com/go-vikunja/vikunja/security/advisories/GHSA-44v6-7fxq-vgf4","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/go-vikunja/vikunja/pull/3239","name":"https://github.com/go-vikunja/vikunja/pull/3239","tags":["x_refsource_MISC"]},{"url":"https://github.com/go-vikunja/vikunja/commit/781ffac198548ae4f3d1febc613caed8e0e11d01","name":"https://github.com/go-vikunja/vikunja/commit/781ffac198548ae4f3d1febc613caed8e0e11d01","tags":["x_refsource_MISC"]},{"url":"https://github.com/go-vikunja/vikunja/releases/tag/v2.4.0","name":"https://github.com/go-vikunja/vikunja/releases/tag/v2.4.0","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":4.3,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"LOW","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-862","lang":"en","description":"CWE-862: Missing Authorization","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-08-28T16:38:38.293Z"},"source":{"advisory":"GHSA-44v6-7fxq-vgf4","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/go-vikunja/vikunja/security/advisories/GHSA-44v6-7fxq-vgf4","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-28T20:29:08.984552Z","id":"CVE-2026-55064","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-28T20:29:30.143Z"}}]}}}